Outdoor gas barbecue grills commonly include auxiliary side burners which are mounted on side shelves outside of the grill firebox. Historically, although useful for some purposes, the capabilities and performance of the side burners installed on outdoor gas grills have fallen far short of the cooking performance, range of uses, and overall functionality of the stove top burners used on indoor cooking ranges. Moreover, the prior art gas side burners have been highly inefficient.
In contrast to indoor burners, outdoor side burners must meet stringent requirements demonstrating that the side burner will continue to operate when exposed to high winds and other conditions encountered in outdoor environments. The failure of the side burner to meet these requirements can result in flame-out (i.e., combustion failure) conditions leading to the hazardous release and potential accumulation of uncombusted gas.
While much effort has been focused on improving the capabilities and cooking performance of outdoor grill side burners to match, as much as possible, the capabilities and functionality of indoor stove top burners, much less attention has been given to improving their efficiency. Rather, to ensure that the outdoor side burners will also pass the requisite wind and combustion tests, the common practice in the industry has typically been to do whatever is expedient to prevent flame impingement conditions and provide a large margin of safety against combustion failure. Consequently, although some improvements in the cooking capabilities of outdoor gas side burners have been achieved, the improved gas side burners typically have not been significantly more energy efficient than the older side burners, and have sometimes been even less so.
A prior art gas side burner 2 configured to meet wind and other outdoor operating requirements is illustrated in FIGS. 1 and 2. The prior art side burner 2 comprises: a burner pan 4 which is installed in a grill side tray 5 of a prior art outdoor grill 7; a burner head 6 which is positioned inside the burner pan 4 below the upper end 8 thereof; a plurality of discharge ports 10 extending around the burner head 6 for discharging a combustible gas fuel (typically a fuel and primary air mixture) for combustion; a fuel line 12 which extends through the bottom of the burner pan 4 for delivering the fuel/air mixture to the burner head 6; a series of secondary air openings 15 formed through the bottom of the burner pan in a circular pattern having a radius greater than the radius of the burner head 6; and a support grate 14 for supporting a cooking pot, pan, or other cooking container 16 a distance above the upper end 8 of the burner pan 4.
To prevent combustion failure due to impingement and/or due to winds, combustion, or other adverse conditions, the burner head 6 of the prior art gas side burner 2 has been spaced a significant distance below the cooking pot support grate 14. Also, to sustain the flame on high wind, typically, higher fuel input is provided at the low valve control setting. In addition, the burner head 6 has typically been of large diameter such that, due to flow patterns within the burner head 6, the fuel/air mixture exiting the discharge ports 10 of the burner head 6 is initially ejected at a downward angle as illustrated by flow arrows 18, thereby causing the resulting combustion flame stream 22 to flow outwardly a greater distance before turning upwardly toward the cooking pan 16.
One detrimental result of the design of the prior art side burner 2 in terms of efficiency and performance is that the large diameter of the burner head 6 and the downwardly angled ejection of the fuel/air mixture from the discharge ports 10 creates a very large central zone 20 beneath the bottom of the cooking pan 16 which is not heated by direct contact with the combustion flame stream 22. For a side burner of typical size for heating a 6 to 11 inch cooking pot 16, the size of this poorly heated zone 20 can be as large as 7 inches in diameter or more. Consequently, for an 11 inch cooking pot 16 positioned on a prior art side burner 2 of this size, only about the outer 2 inches or less of the bottom of the pan 16 are directly contacted by the combustion flame stream 22. Moreover, for a smaller cooking pot, the combustion flame stream 22 can escape without directly contacting the bottom of the pot 16 at all.
In addition, the degree of heat transfer to the bottom of the cooking pot 16 in the poorly heated zone 20 is further diminished due to the typical structure of the prior art support grate 14 upon which the cooking pan 16 is placed. In many prior art side burners 2, the support grate 14 comprises a plurality of parallel support rods 24 which extend from front to back or from right to left over the top of the burner 2. Rather than permitting a continuous radial flow of flue gases 26 and of the combustion flame stream 22 in all directions along the bottom surface of the cooking pot 16, the parallel support rods 24 act as hurdles which divert the flow of these gases downwardly and create air insulated zones on the bottom of the cooking pot 16.
Consequently, a need exists for an improved gas side burner for an outdoor grill which (a) has improved capabilities for cooking and heating which are more comparable to the capabilities and performance of stove top gas burners used on indoor cooking ranges, (b) provides significantly improved fuel efficiency, (c) significantly increases the direct contact area of the combustion flame stream with the bottom of the cooking pan or pot, (d) significantly reduces or eliminates air insulated zones on the bottom of the cooking pan or pot during operation, and (e) meets or exceeds all combustion and other requirements for operating in high winds and in other adverse outdoor conditions. Additionally, a continuing need exists for advances in the art which will not only improve the performance of outdoor burners, but will improve the performance of indoor burners as well.